Data visualization commonly refers to techniques utilized to communicate data or information by encoding it as visual objects that can be displayed via a computer. Visualization is an essential component of any data analysis and/or data mining process. In many instances, a graphical representation of the geometry and topology of a data distribution can enable selection of appropriate analysis tools revealing further insights, and the interpretation of the results. In the era of “big data”, the key bottleneck in the extraction of actionable knowledge from high dimensionality data sets is often a user's (in)ability to visualize patterns in more than 3 dimensions.
Computer displays typically display information in two dimensions (2D). However, a variety of three-dimensional (3D) display technologies are emerging that simulate depth through a number of different visual effects including stereoscopy in which images rendered from different viewpoints are displayed separately to the left and right eye. The two images are then combined in the brain to give the perception of 3D depth. A number of head mounted 3D display technologies are currently available. Paul Milgram and Fumio Kishino, in a paper entitled “A Taxonomy of Mixed Reality Visual Displays” published in IEICE Transactions on Information Systems, Vol. E77-D, No. 12 in December 1994 (the disclosure of which is incorporated by reference herein in its entirety) proposed the concept of a “virtuality continuum” that relates to the mixture of classes of objects presented in any particular display situation, where real environments constitute one end of the continuum, and virtual environments constitute the opposite end of the continuum. In their paper, Milgram and Kishino explain the difference between virtual reality and mixed reality as follows:
“The conventionally held view of a Virtual Reality (VR) environment is one in which the participant-observer is totally immersed in, and able to interact with, a completely synthetic world. Such a world may mimic the properties of some real-world environments, either existing or fictional; however, it can also exceed the bounds of physical reality by creating a world in which the physical laws ordinarily governing space, time, mechanics, material properties, etc. no longer hold. What may be overlooked in this view, however, is that the VR label is also frequently used in association with a variety of other environments, to which total immersion and complete synthesis do not necessarily pertain, but which fall somewhere along a virtuality continuum. In this paper we focus on a particular subclass of VR related technologies that involve the merging of real and virtual worlds, which we refer to generically as Mixed Reality (MR).”    (Milgram, Paul, and Fumio Kishino. “A taxonomy of mixed reality visual displays.” IEICE TRANSACTIONS on Information and Systems 77.12 (1994), p. 1321).
Within the realm of mixed reality, a further distinction can be drawn between Augmented Reality (AR), and Mixed Reality (MR). Both AR and MR displays can be implemented using transparent display technology and/or by capturing images of a scene and using the captured images to render displays combining the real world scene and the virtual objects. The term AR is typically used to describe 3D display technologies that display virtual objects that provide contextually relevant information to a real world scene. AR is often used to refer to an experience in which real world objects are augmented or supplemented by computer-generated sensory input. MR, sometimes referred to as hybrid reality, typically involves the merging of real and virtual worlds to produce new environments and visualizations where real and virtual objects co-exist and interact in real time.
AR, MR, and VR displays can all have a similar goal of immersing a user in an environment that is either partially or entirely virtual. With AR and MR, users continue to be in touch with the real world while interacting with virtual objects around them. With VR, the user is isolated from the real world while immersed in a world that is completely synthesized (although may include virtual analogues to real world objects).